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A most often asymptomatic, sporadically occurring disorder resulting in cystic dilatation of the collecting tubules of the kidneys. Complications include urinary tract infections, hematuria, nephrocalcinosis, and, rarely, renal dysfunction.

Medullary Sponge Kidney (MSK); Precaliceal Canalicular Ectasia; Ricci-Cacchi Syndrome.

Described in 1948 and named after R. Cacchi, an Italian urologist, and V. Ricci, an Italian radiologist.

Up to one in 200 urograms may show signs of Cacchi-Ricci syndrome (CRS). The actual incidence in the general population is not exactly known (because it may be asymptomatic), but the estimated incidence ranges from 1:5000-10,000. CRS has been found in 13% of 800 patients with calcium urolithiasis, with a higher frequency in women (19%) than in men (12%). However, in most series, men are more frequently affected than women, but morbidity seems to be higher in females. No racial predilection has been reported.

Most cases are sporadic, although a few familial cases have been described.

The exact pathophysiology is unknown. However, most researchers consider CRS to be a developmental defect affecting the formation of the collecting tubules, whereas others consider it a primary progressive degeneration of the collecting tubules manifesting later on in life. The kidney size is usually normal or slightly enlarged. Histopathologic examination reveals cystic dilatation of the distal collecting tubules. Proximally, these cysts often communicate with the collecting tubules, while distally they are connected to the papillary ducts or the renal calyx. The cysts often contain calculi.

Made on radiologic findings (sonography, plain radiography, intravenous urography, computed tomography scanning) and/or confirmed by histopathology (renal biopsy). Nephrocalcinosis is a common finding and often is the symptom that results in discovery of the disease (abdominal radiographs taken during evaluation of urinary tract infections or abdominal pain). Most patients remain asymptomatic throughout their life, but a minority of patients develop symptoms (typically in the second or third decade of life) that often are related to complications such as infection, hematuria, and nephrocalcinosis rather than to the CRS itself. The disease process may affect only one medullary pyramid in one or both kidneys or involve several medullary pyramids diffusely in both kidneys.

Common features are pain (38%), ureteral colics (28%), polyuria (28%), urinary tract infections, or hematuria. Often it is an incidental finding during evaluation of the abdomen or the urinary tract for other reasons. In the absence of complications, the overall renal function is and remains normal. Other features can include hypercalciuria (common), hyperuricosuria, urolithiasis, acidification of the urine, or impairment of urinary concentration. If renal involvement is segmental, surgical resection may be beneficial. A higher incidence of Wilms tumor and other abdominal malignancies has been reported in patients diagnosed with CRS during childhood. Regular followup in this population is mandatory.

Assess renal function and evaluate for recurrent urinary tract infections and hematuria. In the absence of complications, CRS does not require therapy. However, the progression of ...

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